Some types of display devices, such as projectors, employ light modulators like digital micromirror devices (DMD's) to modulate light in accordance with image data. A light modulator like a DMD has a given resolution of pixel areas, and generally the resolution of the display device itself matches the resolution of the DMD or other light modulator that the display device uses. However, more recently a technique has been introduced in which the resolution of the display device is increased beyond the resolution of its DMD or other light modulator.
For instance, a mirror or lens may be moved back and forth to direct the light modulated by the DMD or other light modulator in different directions, so that a given pixel area of the DMD or other light modulator can be used for more than one pixel of the display device. The patent application entitled “Image Display System and Method,” filed on Sep. 11, 2002, and published as U.S. patent application publication No. 2004/0027363, describes such an approach to increasing the resolution of a display device over that of its DMD or other light modulator. However, incorporating such a mirror or lens that performs back-and-forth movement into a projection system can be complicated, resulting in an expensive projector or projection system.